Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• more efficient processes and potentially higher yields compared to the batch processes [23]. The first photoredox-mediated Achmatowicz reaction was reported by Gilmore et al. [13] in batch mode utilizing furfuryl alcohols with Ru(bpy)3Cl2·6H2O as photocatalyst, Na2S2O8 as an oxidant and H2O/DMSO/MeCN

• Information File 1). This reactor was then exposed to sunlight/handmade LED to carry out the Achmatowicz rearrangement reaction. To test the model reaction's feasibility, a stock solution containing ethyl 3-(furan-2-yl)-3-hydroxypropanoate (2a)/Ru(bpy)3Cl2·6H2O/K2S2O8/ACN (2 mL)/DMSO (2 mL)/H2O (4 mL) as a

• details in Supporting Information File 1, Table S1, entries 10–18), it was discovered that a combination of ACN/DMSO/H2O solvent, K2S2O8 oxidant, Ru(bpy)3Cl2·6H2O photocatalyst, and 28–34 °C temperature were the best-suited and optimized reaction conditions. After optimization, our efforts were put

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• decreased the chemical yields as well as the diastereomeric ratios (Table 3, entries 1–4). The higher pKa values of the carbonyl α-proton of 4 (for example, the pKa values of the protons of X-CH2C(O)Ph in DMSO were reported to be 17.1 (X: PhS) [45] and 20.3 (X: Ph2N) [46]) would result in the contamination

• indicated DMSO as the best for the attainment of high yields and diastereoselectivity (entries 1–5 vs 6 in Table 4), we further examined bases in this solvent to find out that t-BuOK behaved nicely, and the reaction of 2b with 2.0 equiv of diethyl malonate for 0.5 h at room temperature furnished 93% yield

• , the isolated inseparable mixture of anti,syn-7a and -7b by the reaction of 2b and diethyl malonate was treated with an equimolar amount of DBU in DMSO (rt, 3 h) to furnish products which were identical to the ones obtained in entries 8 or 9 (Table 4). The relative stereochemistry of the isomerized

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• , Japan 10.3762/bjoc.20.203 Abstract An efficient one-step synthesis of diarylacetic acids was successfully performed by electrochemical direct carboxylation of diarylmethanol compounds in DMSO. Constant-current electrolysis of diarylmethanol species in DMSO using a one-compartment cell equipped with a

• showing that electrochemical carboxylation of benzyl alcohols in the presence of Bu4NBH4 in DMF using graphite electrodes gave the corresponding carboxylic acids only in poor yield [18]. We recently found that DMSO is a more suitable solvent for electrochemical carboxylation of benzyl alcohols. Even

• though there was no electron-withdrawing group on the phenyl ring in the benzyl alcohols, electrochemical carboxylation of the benzyl alcohols in DMSO provided the corresponding phenylacetic acids in moderate yield by reductive C(sp3)–O bond cleavage followed by fixation of carbon dioxide at the benzylic

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• with a 1,2,4-triazole-5-thione ring was studied in a MeCN–DMSO mixture to increase its solubility. The first redox transition is detected at early potential values (0.85 V) which coincides with the value obtained for the corresponding starting thiol. However, there is a peak at E = −0.11 V on the

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• -thiomalonate 3 was applied to cyclopentenone, which exhibits electrophilicity on the Mayer scale of −20.60 compared to cyclohexenone (E = −22.10, in DMSO) [41], comparable results were obtained both in solution and in a ball mill (Scheme 5). Therefore, a slightly more reactive electrophile does not

gem-Difluorination of carbon–carbon triple bonds using Brønsted acid/Bu₄NBF₄ or electrogenerated acid

• Mizuki Yamaguchi,
• Hiroki Shimao,
• Kengo Hamasaki,
• Keiji Nishiwaki,
• Shigenori Kashimura and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2024, 20, 2261–2269, doi:10.3762/bjoc.20.194

• , entry 6), but TfOH gave the product 2a in 72% yield (Table 1, entry 7). As for the solvent, CH3CN slightly afforded 2a, although N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) were not suitable for the reactions (Table 1, entries 8–10). A fluorine source, such as Bu4NF or BF3·Et2O, instead of

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• was set to ensure adequate mixing. DMSO and methanol are highly soluble in water, which facilitates handling. Their influence on the viscosity of the CFPS system is negligible, as can be seen in Table 2. The polarities of the different solvents cover a wide range to show the effect on CFPS and give

• water, is better accepted than DMSO. In vitro thscGAS-sfGFP production with additives The CPFS system used, or CFPS in general, is not further optimized for the production of thscGAS-sfGFP or other specific enzymes. By default, GFP is generally used as a model protein to optimize the composition of CFPS

• robust against various technical additives. The general trend is a decrease in protein concentration with increasing concentrations of additives, but still detectable amounts of product were reported with 10% of PEG, choline chloride/urea, betaine/ethylene glycol, DMSO, methanol, and n-hexane. The

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• apparently smaller than those previously reported for the reaction between DBA-OHex and benzyl azide (Table S1 in Supporting Information File 1). However, the Ea values were previously measured in DMSO-d6 and C6D6, and it is known that there is a solvent polarity effect on the reactivity of SpAACs. In order

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• to get the anticipated compound 9. Synthesis of the 5,5,10,10,15,15-hexabutyl-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene (10): Pristine truxene 9 (4 g, 11.68 mmol), DMSO (35 mL), and t-BuOK (11.79 g, 105.12 mmol), were mixed in a two-necked round bottom (RB) flask (100 mL) under nitrogen

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• ) [43]. In parallel, Sheng and Zhang et al. found that 2-(1,3,4-oxadiazol-2-yl)aniline derivatives 38 could be electrochemically synthesized from isatins 35 and acylhydrazine 36. The transformation was carried out in an undivided cell at high temperature in DMSO using potassium iodide as supporting

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• ]. Additionally, when the reaction was performed using DMSO-d6 (or CD3CN) and CH3ONa, H/D exchange occurred already at ambient temperature (25 °C, 20 h) [78]. The formation of CDF=CDF was confirmed by NMR spectroscopy, namely by the change of signal multiplicity in the 19F NMR spectra of E- and Z-isomers of 1,2

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• purified by chromatography (silica [24 g], eluting with EtOAc in hexane from 0–70%) to give methyl 5-bromo-1-alkyl-1H-indazole-3-carboxylate, in 90–98%. For 15a, 284.5 mg, 90%, as a white solid. Mp 141.3 °C; 1H NMR (300 MHz, DMSO-d6) δ 8.19 (dd, J = 1.9, 0.7 Hz, 1H), 7.82 (dd, J = 9.0, 0.7 Hz, 1H), 7.65

• (dd, J = 8.9, 1.9 Hz, 1H), 4.17 (s, 3H), 3.92 (s, 3H); 13C{1H} NMR (75 MHz, DMSO-d6) δ 161.8, 139.4, 132.7, 129.4, 124.1, 123.0, 116.0, 113.0, 51.8, 36.6; IR (KBr disk): 1722, 1466, 1433, 1395, 1354, 1289, 1200, 1183, 1153 cm−1; HRESIMS (m/z): [M + H]+ calcd for C10H10BrN2O2+, 268.9921; found

• ethyl acetate in hexane from 0–60%) to give methyl 5-bromo-2-alkyl-2H-indazole-3-carboxylate in 90–97% yield. For 16a, 291 mg, 92%, as a light pink solid. Mp 110.7 °C; 1H NMR (300 MHz, DMSO-d6) δ 8.14 (d, J = 2.0 Hz, 1H), 7.77 (dd, J = 9.1, 0.7 Hz, 1H), 7.49 (dd, J = 9.0, 1.9 Hz, 1H), 4.42 (s, 3H), 3.98

A new platform for the synthesis of diketopyrrolopyrrole derivatives via nucleophilic aromatic substitution reactions

• Vitor A. S. Almodovar and
• Augusto C. Tomé

Beilstein J. Org. Chem. 2024, 20, 1933–1939, doi:10.3762/bjoc.20.169

• + H+, 100%). Compound 3c. Yield: 53%; mp 252–256 °C; 1H NMR (300 MHz, DMSO-d6) δ (ppm) 10.08 (s, 2H), 7.78 (AA’BB’, J = 8.7 Hz, 4H), 7.55–7.61 (m, 8H), 7.22 (AA’BB’, J = (8.7 Hz, 4H), 5.09 (s, 4H), 2.03 (s, 6H); 13C NMR (125 MHz, DMSO) δ (ppm) 169.1, 164.7, 161.2, 147.3, 139.9, 136.7, 131.6, 130.9

• , 130.6, 129.5, 126.4, 125.4, 120.4, 120.1, 109.3, 31.3, 24.5; 19F NMR (282 MHz, DMSO-d6) δ (ppm) −131.31 to −131.54 (m, 4F), −137.94 to −138.07 (m, 4F); ESIMS m/z: 1011.0 (M + H+, 100%). Compound 3d. Yield: 56%; mp 249–251 °C; 1H NMR (300 MHz, CDCl3) δ (ppm) 8.02 (AA’XX’, J = 9 Hz, 4H), 7.68 (AA’BB’, J

• %; mp 262–265 °C; 1H NMR (300 MHz, CDCl3) δ (ppm) 7.66 (AA’BB’, J = 8.7 Hz, 4H), 7.47 (AA’BB’, J = 8.7 Hz, 4H), 7.28 (AA’BB’, J = 9 Hz, 4H), 6.75 (AA’BB’, J = 9 Hz, 4H), 5.09 (s, 4H), 1.70 (s, 4H), 1.34 (s, 12H), 0.70 (s, 18H); 13C NMR (125 MHz, DMSO) δ (ppm) 161.7, 154.7, 147.3, 145.8, 137.9, 129.9

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts

• Ivana Weisheitelová,
• Radek Cibulka,
• Marek Sikorski and
• Tetiana Pavlovska

Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161

• , 1.0 mmol). As illustrated in Table 1, DMSO was preferred as the optimal solvent, and 130 °C was chosen as the most suitable reaction temperature (Table 1, entry 1). Other solvents showed low yields, or the product was not isolated at all. However, we found that the yield of 5-phenyldeazaalloxazine 2a

• was significantly enhanced when refluxing in DMF with a catalytic amount of AlCl3 compared to the reaction in clear DMF (Table 1, entries 7–9). Other Lewis acids were not as effective, except for a combination of DMSO/TMSOTf (Table 1, entry 4). The application of AcOH/PPA for the synthesis of 5

• heating conditions (CH). Syntheses were performed in DMSO, DMSO/AlCl3, DMF/AlCl3 and AcOH/H2SO4 at 110 °C (Table 1, entries 5, 6, 9, and 12). Under these conditions, the reaction time was significantly reduced to 1 hour from the usual 15 hours, however, the yields stayed in the range of 30%, and the

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• reclassified as Saccharophagus degradans 2-40 [118]. Two additional GH18 chitinases, MtCh509 [50] and rChi1602 [79] were characterized from Microbulbifer thermotolerans DAU221 and Microbulbifer sp. BN3, respectively. MtCh509 was expressed in E. coli. Some organic solvents (benzene, DMSO, hexane, isoamyl

pKalculator: A pK_a predictor for C–H bonds

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2024, 20, 1614–1622, doi:10.3762/bjoc.20.144

• benchmarked against 695 experimentally determined C–H pKa values in DMSO. The ML model is trained on a diverse dataset of 775 molecules with 3910 C–H sites. Our ML model predicts C–H pKa values with a mean absolute error (MAE) and a root mean squared error (RMSE) of 1.24 and 2.15 pKa units, respectively

• (DMSO) using a graph convolutional neural network (GCNN) [3]. Using a mix of experimental and computed pKa data, they achieved a mean absolute error (MAE) of 2.1 pKa units. Lee and co-workers also addressed this problem by creating a general machine learning (ML) model using either a neural network or

• and achieved a MAE of 1.5 pKa units for the solvent DMSO using XGBoost [4][5]. Unfortunately, neither the Grzybowski group nor the Lee group have made their models generally available to other users. Inspired by the efforts of the Grzybowski group and the Lee group, we have developed pKalculator, a

Regio- and stereochemical stability induced by anomeric and gauche effects in difluorinated pyrrolidines

• Ana Flávia Candida Silva,
• Francisco A. Martins and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2024, 20, 1572–1579, doi:10.3762/bjoc.20.140

• differences did not impact the selection of the best levels based on geometry criteria. Regarding the conformational energy, 3-fluoropyrrolidine exhibited four conformers in the gas phase, although this was reduced to three in implicit DMSO experiments (Table 1). In both cases, a cis-twist ring with an axial

• . Consequently, a total of 10 different structures was identified in the gas phase, with two additional structures observed in implicit DMSO (using solvation model density, SMD), bringing the total to 12. Since the atomic composition of the compounds in Figure 4 was the same, the relative energy may be compared

• , and a stability landscape covering all optimized structures may be obtained from this analysis. Among these structures, only six were found to be significantly stable (<3 kcal⋅mol−1) in either the gas phase or DMSO. Remarkably, structure 19 was the most stable, followed by structure 17, as shown in

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• respectively 71%, 41%, and 37% total yields (Scheme 1). Photophysical characterization The photoswitching properties of galactosyl azobenzenes 1–5 were realized in water or in Tris buffer containing 5 to 10% DMSO, in accordance with the biophysical evaluation conditions by using ITC. All these compounds

• Z/E ratios during irradiation, showing an excellent photoconversion yield of Z/E = 99:1 at PSS370, and E/Z = 87:13 at PSS485 in D2O/5% DMSO (Figure 3). As the Z-isomer is metastable, its half-life has been determined to be 44.4 h in water at room temperature (Figure S9 in Supporting Information File

• ITC200 isothermal titration calorimeter (Microcal-Malvern Panalytical, Grenoble, France). The lyophilized LecA protein was dissolved in a buffer composed of 20 mM Tris.HCl (pH 7.5), 100 mM NaCl and 100 μM CaCl2 with 5% or 10% DMSO final. All compounds were first dissolved in DMSO then in same buffer for

Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

• Simone Gräßle,
• Laura Holzhauer,
• Nicolai Wippert,
• Olaf Fuhr,
• Martin Nieger,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

• , THF/pyridine (9:1), −20 °C to 21 °C, 12 h, b) Cs2CO3, DMSO, 120 °C, 2–3 d, c) TFA, TMS-N3, DCM, 25 °C, 12 h, d) 1. TFA, TMS-N3, DCM, 0–50 °C, 12 h; 2. alkyne, THF/H2O, CuSO4, sodium ascorbate, 16 h, 50 °C. Synthesis of triazenylpyrazoles 15a–d and functionalization to N-substituted triazenylpyrazoles

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• phthalides 100, as evidenced by the per-O-methylated derivative of pestalone, a marine natural substance. Either in a Cannizarro–Tishchenko-type reaction with nucleophile catalysis (NaCN) or under photochemical conditions (DMSO, 350 nm), the transformation often proceeds without any problems in DMSO (Scheme

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• yields and the desired stereoselectivity [59][60][61]. The viscous nature of the aminofuranes usually requires the use of toxic solvents such as toluene, and in some studies, solvents such as DMSO, which are difficult to remove from the reaction medium [62][63][64]. Although solvent effects are of little

• reaction, the acylation is followed by an intramolecular Diels–Alder reaction and the amide intermediate (a sample compound has been previously isolated and fully characterized as a result of detailed studies) is in equilibrium with the final product at room temperature in polar solvents such as DMSO

• chloroform-d (CDCl3) or hexadeuterodimethyl sulfoxide (DMSO-d6) as a solvent. Chemical shifts (δ) are reported in ppm and J values in Hertz. The elemental analyses were performed using an LECO CHNS-932 elemental analyzer (Saint Joseph, MI, USA). Representative procedure for the IMDAF reaction to afford 2a In

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• repeated several times to obtain a sufficient amount of the mixture for 77Se NMR spectroscopy. Indeed, two major resonance signals at 371 and 296 ppm were observed in the 77Se NMR spectrum of the mixture recorded in DMSO-d6 (Figure S5, Supporting Information File 1), which could be assigned to diaryl

• )selanyl)aniline (2): Black solid (28.2 mg); 77Se NMR (95 MHz, DMSO-d6, δ) 371.2, 296.1; HRESIMS (m/z): [M + H]+ calcd for C12H13N2Se (ortho/para), 265.0238; found, 265.0229, [M + H − PhNH2]+ calcd for C6H6NSe (ortho/para), 172.0238; found, 171.9667; FTIR (KBr) ν̃max: 3436, 3354, 3220, 3026, 1595, 1490